Which factor is listed as a potential mechanism accompanying secondary/functional MR?

Which factor is listed as a potential mechanism accompanying secondary/functional MR?

• A. Afib
• B. DCMO
• C. Large VSD
• D. Significant AR

Answer: (B)

Functional (secondary) MR happens when the mitral valve itself is structurally normal, but the surrounding heart geometry distorts enough to prevent proper leaflet closure. The classic driver of this distortion is left ventricular dilation and remodeling. In dilated cardiomyopathy, the ventricle enlarges and reshapes, pulling the papillary muscles apart and expanding the mitral annulus. This tethering of the leaflets and annular dilation prevent complete coaptation, producing mitral regurgitation despite normal valve leaflets. So dilated cardiomyopathy is a textbook mechanism for secondary/functional MR because it directly creates the geometric changes that cause the regurgitation. Atrial fibrillation can contribute by enlarging the left atrium and annulus, but the primary, well-recognized mechanism highlighted here is LV remodeling from dilated cardiomyopathy. Large VSD or significant aortic regurgitation don’t explain the typical functional MR mechanism in the same way.

Functional (secondary) MR happens when the mitral valve itself is structurally normal, but the surrounding heart geometry distorts enough to prevent proper leaflet closure. The classic driver of this distortion is left ventricular dilation and remodeling. In dilated cardiomyopathy, the ventricle enlarges and reshapes, pulling the papillary muscles apart and expanding the mitral annulus. This tethering of the leaflets and annular dilation prevent complete coaptation, producing mitral regurgitation despite normal valve leaflets.

So dilated cardiomyopathy is a textbook mechanism for secondary/functional MR because it directly creates the geometric changes that cause the regurgitation. Atrial fibrillation can contribute by enlarging the left atrium and annulus, but the primary, well-recognized mechanism highlighted here is LV remodeling from dilated cardiomyopathy. Large VSD or significant aortic regurgitation don’t explain the typical functional MR mechanism in the same way.